Induction heating



Jane 1, 1960 Filed Feb. 17, 1958 J. K. MCLAUGHLIN ETAL 2,939,591

mnucnou HEATING 2 Sheets-Sheet 1 All INVENTOR. James K. McLauy/y/fn IA /'//'am E Mered/f/r A TOENFYS.

June 1960 J. K. MOLAUGHLIN nu. 2,939,591

INDUCTION HEATING Filed Feb. 17, 1958 2 Sheets-Sheet 2 INVENTOR. James K. McLoqy/r/uv BQVi/l/am E Mered/fh 4 W United States Patent h INDUCTION HEATING James K. McLaughlin and William Fenton Meredith, Youngstown, Ohio, assignors to Ajax Magnethermic Corporation, a corporation of Ohio Filed Feb. 17, 1958, Ser. No. 715,780

16 Claims. (Cl. 214-23) Our device relates to continuous feed induction heating furnaces of the type wherein a plurality of billets are fed sequentially into one or more induction coils, each billet being passed therethrough by movement of the succ'eeding billet- More particularly, our invention pertains to a device for removing heated billets from the said furnace without introducing more billets therein.

f Continuous feed furnaces of this type have several disadvantages which my invention overcomes. For example, at the end of a run, partially heated billets are still in the coils and must be moved through said coils at the same rate as preceding billets if they are to be properly heated.v A similar situation arises when there is a breakdown in one of the coils or a stoppage in a related portion of the billet heating process.

Also, heated billets aresubject to scale formation if left in the furnace to cool. If cold billets are in the furnace when it is energized, the billets nearest the ejection end of said furnace will be insufliciently heated and must, therefore, be returned to, the feeding end for reheating. In modern, assembly line production, such duplication of effort results incostly losses in time.

. An additional disadvantage is evident when one of a series of coils breaks down and must be removed from the furnace. The presence of billets in the coils greatly hampers and complicates the removal and repair of a single coil.

fItis, therefore, an object of our invention to provide a device, for removing heated billets from an induction heating {furnace after the last of said billets has been insenedf f Anotherobject of our invention is'to provide such a device which will index the remaining billets through the furnace at the. proper rate for the heating thereof.

[Still another object of our-invention is to provide a device of the above type which can be readily used without major changes in the ordinary indexing apparatus.

Yet another object of our invention is to provide such a 'device-which'is simple and easy to manufacture and comprised of but few parts. T

A further object of our invention is to provide a device of the above type which is positive in action and highly durable in use.

Other objects of our invention and the invention itself will be readily apparent from the following specification and the appended drawings, in which said drawings:

' Fig. 1 is a top plan view of an induction heating furnace and the feeding mechanism for propelling the billets therethrough;

- .Fig. 2 is a view taken along the line 2-2 of Fig. 1;

Fig. 3 is an end view of the furnace of Figs. 1 and 2 as seen from the' loading endthereof;

Fig. 4 is a longitudinal section of the loader of my invention;

Fig. 5 is a section taken along the line 5-5 of Fig. 4;

2,939,591 latented June 7, 1960 Referring now tothe figures of the drawings, in all of; which like parts are designated by like reference charac-' ters, at 1 we showan induction heating furnace comprising a plurality of coaxial coils 2 mounted upon a base 3. Adjacent the loading end of the furnace, designated by the numeral 4, we provide aloading mechanism generally shown at 5. Said loading mechanism comprises a con veyer6, a trough-shaped tilting mechanism 7 tiltably actuable by a cylinder 8, a trough-shaped billet car 9 reciprocally actuated by a cylinder 10, and a ram-type loader 20.

Theloader 20 is longitudinally aligned with the furnace 1 whereby it is adapted to feed-billets 11 into said furnace. The conveyer 6 and the tilting mechanism 7 are positioned parallel with andto one side of the loader 20 and provide-a continuous, downwardly sloping runway. ,The'

car 9 is adapted to move from an aligned position in front of saidloader to an aligned position at the lower end of said conveyer.

In the form of our invention as herein illustrated, the

loader 20' tolbe inserted at the loading end 4 of the' furnacel.

Our invention is particularly concerned with the loader 20, and the above description of an entire feeding mechanismis given to provide an understanding of the relationship between our device and an induction heating furnace. It will be understood that our invention is not restricted to a specific type of feeding mechanism and that. it is readily adaptable for all types of continuous feed furnacesl- Referring now to Figs. 4 to 8 inclusive and particularly to Fig. 4, the loader 20 comprises a cylindrical housing 21 into which is mounted a reciprocating piston rod 22 havinga rigidly'mounted coaxial piston 23.; The piston rod 22 is tubular thereby providing an axial bore 24, and said rod projects forwardly and rearwardly beyond end walls 25 and 26 respectively of the housing 21 through bearing apertures 25a and 26a therein. a

The forwardly directed end of the. piston rod 22 is coaxially thread-fitted within a' loader head 27 having a coaxial bore "27a extending longitudinally therethrough. The axialbore 24 of thepiston rod 22 and the axially.

aligned bore 27a of the head 27' provide a longitudinally continuous. aperture into which acleanout ram 28 is slidably interiitted. The .ram 28 is substantially longer than, the combined piston rod.,22and'head 27 and projects forwardly and rearwardly therefrom. A dummy billet 29 is secured to theforward end of the ram 28, which end projects in the direction of the furnace 1.

The'dummy billet 29 is preferably secured to the forward end of the said ram by means of a socket 60 in a rearwardly projecting reduced portion 61 of said dummy billet into which the ram is projected. A U-shaped locking pin 62 projects through parallel apertures 63 in the reduced portion 61, the legs 64 of said pin laterally engaging a groove 65 in the ram 28 to secure said billet against longitudinal displacement.

Asbest shown in Figs. 4 and 5, the head 27 is substantially, cylindrical in shape and is provided with a set screw 30 adjacent the, rearward end thereof whereby it is retained =against rotational movement on the pistonv ro'd '22. "In the form'ofem invention as herein illus trated, the head '27 is longitudinally milled at two points in its outer circumference to form substantially identical channels 31 having parallel, interspaced side walls 32 and arcuately formed bottom walls 33. The bottom Walls 33 define an arc intersecting the bore 27a thereby providing an opening 34 at the bottom of the channels 31. By means of the opening 34, the ram 28 positioned in the bore27a is exposed within each of the channels 31 at the bottom thereof.

Referring now particularly to Fig. 5, the channels 31 are positioned at right angles to each other on center lines radiating from the center of the head 27. A ramgripping jaw' 40 is pivotally mounted within each of the channels 31 by means of eccentrically mounted pivot shafts 41. Each of the jaws 40 comprise a loosely inter.- fitting block having radially inwardly directed, laterally concave, longitudinally convex gripping surfaces 42. The radially outermost surfaces 40 of the jaws 40 are provided with laterally directed, generally V-shaped grooves 40a. 4 V

i The pivot shafts 41. comprise laterally directed journals 43 and 44 mounted in apertures 35 and 36 respectively of the head 27 and intermediate, eccentric pivots 45. The journals 43 are preferably relatively larger than the journals 44 and are provided with tapered threaded sockets 43d and diametric slots 43b. A tapered threaded plug 46 is fitted within each of the sockets 43a and isadapted to expand the journal 43 when tightening within said socket. It will be understood, therefore,

that by tightening the plugs 46, the pivot shafts 41 are maintained against rotational movement by means of the expanded journals 43 frictionally engaging the apertures 35.

The relatively smaller journals 44 are coaxial with the journals 43 and are provided with slots 44a whereby the pivot shafts 41 can be rotated when the journal 43 has been loosened;

The eccentric pivots 45 project within the channels 31 whereby the jaws 40 are pivotally mounted. Said jaws are mounted upon said eccentric pivots by means of apertures 47 and bearings 48 and are radially adjustable relative to the head 27 by means of said eccentric pivots. When it is desired to adjust the jaws 40, the plugs 46 are loosened and the journals 44 are rotated to move the eccentric pivots 45, toward or away from the center of the head 27.

The head 27 is provided with preferably three circumferential, generally V-shaped grooves 37, 38, and 39. Said grooves are immediately adjacent each other and e unusuall c te e an e head 2 the d a groove 38 being substantially aligned with the pivot shaft 41 whereas the groove. 37 is forward of said shaft and the groove 39 is rearwardly positioned therefrom. As best shown in Fig. 4, it will be noted, therefore, that the grooves 40a in the jaws 40, the groove 38 in the head 27 and the pivot shaft 41 are all vertically substantially aligned.

A circumferentially continuous coil spring 57 is positioned in the groove 38 and the grooves 40a aligned therewith whereby the jaws 40 are resiliently maintained in a horizontal position. In such position, the gripping surfaces 42 of said jaws are spaced radially outwardly from the ram 28 and do no make contact therewith. The spring 57 is circumferentially contained within an internal groove 58 of a retainer ring 49 surrounding the head 27. Longitudinal grooves 49a in the retainer ring 49 are provided adjacent the jaws 40 whereby the outermost surfaces of said jaws are spaced away from said retainer ring. From the foregoing description it will be understood that the jaws 40 are maintained in a nonengaging position relative to the ram 28 by means of the spring 57 in the retainer ring 49 (Figs. 4 and In this position of the jaws 40, the ram 28 is, therereff sel li eble Wi hi t e l dr 2 and it th me .7 and t hi F9 x 22 esp ctiv ly- Referring now to Figs. 6 and 7, the spring 57 is longitudinally movable in a forward or rearward direction by manual movement of the retainer ring 49 to positlons whereby said spring enters either the groove 37 or the groove 39. At such times, said spring leaves the grooves 48a of the jaws 40 and contacts the outer surfaces 43 thereby pivoting said jaws into contact with the ram 28. Suitable stop means such as bolts 50 and 51 in the head 27 limit the longitudinal forward and rearward movement of the retainer ring 49 to the optimum position for placing the spring 57 into the grooves 37 and 39 respectively.

The piston rod 22 reciprocates within the housing 21 of the loader 20 in a conventional manner comprising the alternate introduction of pressurized fluid into the ends of said housing on either side of the piston 23. Fluid is introduced at the forward end of the housing 2 1 by means of a passage 15 extending through the front end wall 25 and said fluid is introduced at the rearmost end of said housing by means of a passage 16 in the rear end wall 26.

The stroke of the loader 20 is such that the billets 11 are moved through the furnace 1 at the optimum rate for proper heating. in normal operation, the ram 28 and the dummy billet 29 are removed, and the billets 11 are propelled by the reciprocating movement of the head 27.

When it is necessary to clear the furnace of billets already inside without the insertion of new billets, the ram 23 and the dummy billet 29 are mounted in the loader '20 as shown in Fig. 4. The retainer ring 49 is then moved to the position as shown in Fig. 7 whereby the jaws 40 are tilted forwardly. As the piston rod 22 makes its forward stroke as indicated by the arrow, the jaws 40 firmly grip the ram 28 and carry the same along with it. This gripping action results from the fact that the jaws 49 are being urged in a counterclockwise direction by the resistance of the ram 28 frictionally contacting the gripping surfaces 42 of said jaws. The more resistance presented by the ram 28, the tighter the jaws 40 wedge against said ram.

On the return stroke the effect of the jaws upon the ram is just the opposite. The jaws 40 are then urged in a clockwise direction away from the ram 28, and the weight of the dummy billet 29 holds said rarn at its most advanced position while the piston rod 22 and head 27 move rearwardly around said ram. Each forward stroke of the piston rod 22 moves the ram 28 and dummy billet 29 forward thereby indexing it through the furnace to clear the billets therefrom at their normal rate of movement.

After the furnace 1 has been cleared and it is necessary to remove the ram 28 and dummy billet 29 from said furnace, the retainer 49 is moved to the position as shown in Fig. 6 whereby the spring 57 is positioned in the groove 39. This adjustment causes the ram 28 to be gripped bythe jaws 40 during the retracting or rearward stroke of the piston rod 22 thereby withdrawing said ram and billet from the furnace.

To aid in the gripping of the jaws 49 upon the ram 28, the gripping surfaces 42 of said jaws may be roughened, knurled, coated, or otherwise modified to increase the frictional contact between said jaws and said ram. Additionally, the number of jaws 40 may be increased to three or four and may have different circumferential spacings. In some instances a single jaw would be sufficient. We anticipate that the above recited factors would be variable to meet different needs depending upon the size of the ram, the size of the billets, the weight of the dummy billet, the stroke of the loader, etc. The form as shown herein having a pair of jaws 40 is given to illustrate the principle of our invention and is not intended to limit the scope thereof.

During the billet clearing operation, the coils 2 of the furnace 1 are de-energiaed successively from the mouth w s an rain 28 and extending substantially the length thereof.

The forward end of said ram is plugged as shown at 7 1, and the forward end of the tube 70 is spaced rear wardly'from said plug. 7 The tube 70 projects outside of the ram 28 adjacent the rearmost end thereof and is connected to a preferably flexible hose73. The rearmost end of the ram 28 is provided with a fitting 74 which provides attachment means for a hose 75. The tubular ram 28, is spaced radially away from the tube 70 whereby a cooling liquid introduced through the hose 73 and said tube 70, passes rearwardly through said ram and is expelled through the fitting 74 and the hose .75.

It, will be understood that many departures from the detailslof. our. invention mayjbe made, such as changes in size and dimension, without, however, departing from thespirit of our invention or the scope of the appended claims.

What we'claim is: p

, 1. A device for removing billets from a continuous feed. furnace comprising" a reciprocating member, means for reciprocatively actuating said member, a ram a'sso; ciatedwith said reciprocating member and movable relative; thereto, ,and gripping means mountedupon said reciprocating member ada t d to effect progressive movements ofsaid ramwith said. member in one direction I only; r51 I I ram slidably mounted within said tubular member, a

gripping element mounted on one end of said tubular member, said gripping element having at least one pivoted jaw adapted to frictionally engage said ram when said tubular member is moved in one direction to move said ram progressively in the same direction.

4. A device for removing billets from a continuous feed furnace comprising a tubular member, means for longitudinally reciprocating said member, a ram slidably mounted within said tubular member, a gripping element mounted on one end of said tubular member, said gripping element being apertured coa-xially-with said tubular member, said ram projecting through said gripping element, said gripping element having at least one pivoted jaw adapted to be tilted to either of two pivoted positions whereby it contacts said ram, and means for selectively tilting said jaw to either of said pivoted positions.

5.'A device forv removing billets from a continuous feed furnace comprising a tubular member, means for longitudinally reciprocatively moving said member, a gripping element mounted on one end of said tubular member and being apertured coaxially with said tubular member, a ram slidably mounted within said tubular member and said gripping element, said gripping element having at least one pivoted jaw adapted to be tilted in at least one pivoted direction, whereby said jaw engages said ram to move the same with the movement of said In Fig. 4 we illustrate such a cooling system com tubular element in one direction, said jaw adapted to slide relative to said ram when said tubular element moves in the opposite direction.

6. A device for removing billets from a continuous feed furnace comprising a tubular member, means for longitudinally reciprocatively moving said member, a gripping element mounted on one end of said tubular member and being apertured coaxially with said tubular member, a ram slidably mounted within said tubular member and said gripping element, said gripping element having at least one pivoted jaw alternately tiltable to two pivoted positions whereby said jaw contacts said ram, said jaw having an intermediate, nontilted position 4 wherein said jaw does not contact said ram, a first of said pivoted positions effecting engagement of said jaw with said ram to move said ram in one direction only with the movement of said tubular member, the second of said pivoted positions effecting engagement of said jaw with said ram to move said ram in the opposite direction only from said first position, and means for selectively pivoting said jaw to either of said pivoted positions or said intermediate position.

7 A gripping element for mounting upon one end of a reciprocating, tubular piston rod, said gripping element being apertured coaxially with said piston rod and adapted to receive a ram slidably projecting through said piston rod and said gripping element, said gripping element having at least one jaw mounted upon a lateral pivot of said gripping portion, said jaw alternately longitudinally tiltable to two pivoted positions whereby said jaw contacts said ram, said jaw having an intermediate, nontilted position wherein said jaw does not contact said ram, a first of said pivoted positions effecting engage ment of said jaw with said ram to move said ram in one direction only with the movement of said tubular member, the second of said pivoted positions effecting engagement of said jaw with said ram to move said ram in the opposite direction only from said first position,

said jaw projecting radially beyond said gripping element, a tensioned coil spring surrounding said gripping element and contacting said jaw and adapted to efiect the til-ting thereof, said grippingelement providing a plurality of seating means for said spring corresponding to the pivoted positions of said jaw and the intermediate nontilted position thereof whereby said jaw is selectively adjusted to any of the recited positions by movement of said spring from one to another of said seating means.

8. A device as set forth in claim 7 wherein the recited lateral pivot comprises a pair of axially aligned journal portions having interposed therebetween an eccentric pivot portion, said journals rotatably mounted in said gripping element and said jaw pivotally mounted on said pivot portion.

9. A device for removing billets from a continuous feed furnace comprising a housing, a tubular piston rod and a piston mounted within said housing for reciprocating movement relative to said housing, said piston rod projecting longitudinally beyond said housing, a gripping element mounted upon one end of said piston rod and apertured coaxially with said piston rod, a ram slidably mounted within said piston rod and said gripping element and extending longitudinally therefrom, said gripping element having at least one pivoted jaw adapted to be longitudinally tilted whereby said jaw engages said ram to move it in one direction only with said piston rod, said iaw adapted to slide relative to said ram when said piston rod is moved in the opposite direction.

10. A device for removing billets from a continuous feed furnace comprising a housing, a tubular piston rod and a piston mounted within said housing for reciprocating movement relative to said housing, said piston rod projecting longitudinally beyond said housing, a gripping element mounted upon one end of said piston rod and apertured coaxially with said piston rod, a ram slidably mounted withinsaid pistourod and said gripping element and extending longitudinally therefrom, said gripping ele ment having at least one jaw mounted upon a pivot and adapted to be longitudinally tilted to two oppositely pivoted adjusted positions in each of which said positions said jaw engages said ram to move the same in one direction only with said piston rod, said jaw having an intermediate adjusted position in which said jaw does not engage said ram, and resilient means associated with said gripping element adapted to selectively bias said jaw to each of the recited adjusted positions.

11. A device as set forth in claim 10 characterized by the recited jaw extending radially outwardly beyond said gripping element, and wherein the recited resilient means comprise a coil spring surrounding said gripping element and contacting said jaw, said coil spring being movable to contact said jaw at different longitudinal points corresponding to the recited adjusted positions of said jaw, and means for retaining said spring at each of the recited longitudinal points.

12. A device for removing billets from a continuous feed furnace comprising a housing, a tubular piston rod and a piston mounted within said housing for reciprocating movement relative to said housing, said piston rod projecting longitudinally beyond said housing, a cylindrical gripping element mounted coaxiaily upon one end of said piston rod and being coaxially apertured relative thereto, a ram slidably mounted within said piston rod and said gripping element and extending longitudinally therefrom said gripping element having at least one jaw mounted upon a laterally disposed pivot in said gripping element, said jaw longitudinally tiltable to oppositely pivoted adjusted positions wherein said jaw engages said ram to move the same in one direction only with said piston rod, said oppositely pivoted adjusted positions effecting oppositely directed movements, said jaw having an intermediate adjusted position wherein said jaw does not engage said ram, said jaw extending radially beyond said gripping element, said gripping element having a plurality, of circumferential grooves one of which defines a plane aligned with the axis of said pivot, the other of said grooves being longitudinally symmetrically arranged relative to said first mentioned groove, a continuous coil spring adapted to be selectively seated within said grooves 8 and contacting :saidjaw to resiliently maintain the same in the recited adjusted positions.

13. A device as set forth in claim 12 including therewith means for cooling said ram.

14. A device as set forth in claim 12 wherein the recited ram comprises a tubular member closed at one end thereof and having an outlet at the opposite end thereof, a relatively small tube loosely positioned within said tubular member having an end thereof adjacent the closed end of said tubular member, said tube having the opposite end thereof projecting outside of said tubular member adjacent said outlet end, the combination adapted for the continuous circulation of a cooling liquid between the outwardly projecting end of said tube and the outlet end of said tubular member.

15 A device for indexing successively introduced billets through a continuous feed furnace adapted to also effect the final removal of the last introduced of said billets from said furnace, said device comprising a reciprocating member, means for actuating said member whereby said successively introduced billets are moved in one direction by said reciprocating member, a removable ram associated with said reciprocating member and movable relative thereto, gripping means mounted upon said reciprocating member adapted to effect progressive movements of said ram with said reciprocating member in one direction only, said ram adapted to move said last introduced billets through. said furnace.

'16. A fluid device for indexing successively introduced billets through a continuous feed furnace, said device comprising a fluid cylinder, a reciprocating tubular piston rod mounted in said cylinder, said rod being provided with a billet engaging end, meansadapted to be longitudinally and reciprocably. disposed within said tubular piston rod and associated with the billet engaging end of said piston rod for movement of a billet in a discharge direction, said means adapted to have a continuous movement in one direction during successive forward movements of said piston rod.

References Cited in the file of this patent UNITED STATES PATENTS 2,328,388 Morgan et al. Aug. 31, 1943 

